Positive displacement air and gas compressors, including helical screw and rotary vane types, require substantial starting torque if the compressor is started without throttling the inlet gas flow. Accordingly, compressors driven by electric motors require substantial current flow to start the compressor. However, limitation of starting current and voltage fluctuation can be important for energy conservation, and for many applications of electric motor driven compressors reduced voltage starters are therefore desirable. Reduced voltage starters provide for a gentle startup and smooth acceleration to running speed but limit the starting torque of the motor. Accordingly, it is desirable to provide automatic load control for the compressor to meet the starting torque capability of the motor.